Fluid Ejection Device with Data Storage Structure

ABSTRACT

A fluid ejection device having storage and methods of forming and using such fluid ejection devices are described. In one embodiment, a substrate comprises multiple heater resistors supported thereby, and configured for ejecting fluid onto a medium. One storage structure is supported by the substrate and configured to store data.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of copending U.S. utility applicationentitled, “Fluid Ejection Device With Data Storage Structure,” havingSer. No. 10/434,759, filed May 9, 2003, which is entirely incorporatedherein by reference.

TECHNICAL FIELD

This invention relates to fluid ejection device methods and systems.

BACKGROUND

One type of fluid ejection device is an ink jet printer. The art of inkjet printing is relatively well developed. Commercial products such ascomputer printers, graphics plotters, and facsimile machines have beenimplemented with ink jet technology for producing printed media.

Generally, an ink jet image is formed pursuant to precise placement on aprint medium of ink drops emitted by an ink drop generating device knownas an ink jet printhead. Typically, an ink jet printhead is supported ona movable print carriage that traverses over the surface of the printmedium and is controlled to eject drops of ink at appropriate timespursuant to command of a microcomputer or other controller, wherein thetiming of the application of the ink drops is intended to correspond toa pattern of pixels of the image being printed.

One embodiment of a Hewlett-Packard ink jet printhead includes an arrayof precisely formed nozzles in an orifice plate that is attached to anink barrier layer which in turn is attached to a thin film substructurethat implements ink firing heater resistors and apparatus for enablingthe resistors. The ink barrier layer defines ink channels including inkchambers disposed over associated ink firing resistors, and the nozzlesin the orifice plate are aligned with associated ink chambers. Ink dropgenerator regions are formed by the ink chambers and portions of thethin film substructure and the orifice plate that are adjacent the inkchambers.

The thin film substructure is typically comprised of a substrate such assilicon on which are formed various thin film layers that form thin filmink firing resistors, apparatus for enabling the resistors, and alsointerconnections to bonding pads that are provided for externalelectrical connections to the printhead. The ink barrier layer istypically a polymer material that is laminated as a dry film to the thinfilm substructure, and is designed to be photodefinable and both UV andthermally curable. In an ink jet printhead of a slot feed design, ink isfed from one or more ink reservoirs to the various ink chambers throughone or more ink feed slots formed in the substrate. Examples of ink jetprintheads are set forth in commonly assigned U.S. Patent Nos. 4,719,477and 5,317,346. In another embodiment, the barrier layer and orificeplate are integral.

During and after the manufacture of ink jet printheads, it is desirableto develop and store data associated with the printhead. Such data caninclude the wafer lot, wafer number, color, and other information. Thisdata can be stored using an off chip or off die EEPROM. Alternately, thedata can be stored on the die itself.

In the past, storing data on the die itself has involved the use ofseparate fusible links or fuses. The fuses have typically beenfabricated as TaAl resistors. One of the issues associated with usingon-die fuses stems from the fact that in order to program the fuse, itis electrically blown to define an open circuit. Blowing a fuse on thedie, however, can do a significant amount of thermal damage to thesurrounding thin film structure. Specifically, blowing an on-die fuseentails breaking overlying passivation layers, melting structureunderneath the layers, and the like. Normally, this would not be anissue for substrates that are used in a hermetically-sealed, dryenvironment. With the ink jet product, however, due to the nature of thefluidic environment in which it operates, even in view of the variousbarrier materials that can be used to isolate the fuses, there still isa very real possibility for failure to occur due to ink leaking into thefuse area. This is an undesirable situation because not only can storeddata be lost, but there is a chance that the overall functionality ofthe die itself can be compromised.

SUMMARY

A fluid ejection device having storage and methods of forming and usingsuch fluid ejection devices are described. In one embodiment, asubstrate comprises multiple heater resistors supported thereby, andconfigured for ejecting fluid onto a medium. One storage structure issupported by the substrate and configured to store data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram that illustrates an ink jet printhead substratehaving a heater resistor array and storage structures in accordance withone embodiment.

FIG. 2 is a graph that describes characteristics of annealed versusunannealed resistor material in accordance with one embodiment.

FIG. 3 is a flow diagram that describes steps in a method in accordancewith one embodiment.

FIG. 4 is a circuit diagram that illustrates an exemplary ink jetprinthead heater resistor layout, and is useful in understanding one ormore of the described embodiments.

FIG. 5 is an isolated view of an exemplary primitive group and is usefulin understanding one or more embodiments.

FIG. 6 is a table that can be utilized in accordance with one or moreembodiments.

FIG. 7 is a flow diagram that describes steps in a method in accordancewith one embodiment.

DETAILED DESCRIPTION

Overview

Various embodiments provide methods and resultant structures that employon-die, non-volatile, non-fusable storage structures on ink jetprinthead die. Because resistor material is used to store data in amanner which does not require it to be subjected to fuse-blowingprocesses, most if not all of the issues associated with thefusing-blowing processes are mitigated.

Using Resistor Material as a Non-fusible Storage Structure

In accordance with one embodiment, on-die resistor material is used as anon-fusible storage structure. Using on-die resistor material fornon-fusible storage material employs the resistor material to providePROM-like storage capabilities. Because the resistor material is used tostore data in a manner which does not require it to be subjected tofuse-blowing processes, most if not all of the issues associated withthe fusing-blowing processes are mitigated. Specifically, the resultantthermal damage to surrounding thin film substrate material issubstantially avoided. Accordingly, the risk of failure due to fluidiccompromise is also reduced.

In selecting a resistor material for use as a non-fusible storagestructure, various described embodiments can make use of a material thathas the following characteristic. The material has a first resistancevalue before it is annealed and a second different resistance valueafter it is annealed. By selecting a material that has a resistancevalue that is a function of whether or not it has been annealed,individual storage structures can be formed on the die substrate. In onestate (e.g. the unannealed state), the storage structure can represent afirst digital value such as a 1 or 0. In the other state (e.g. theannealed state), the storage structure can represent a second digitalvalue—the compliment of the first digital value.

Additionally, in one embodiment the storage structures can be formedcontemporaneously with and using the at least some of the same processflow that is utilized to form the regular heater resistors that areemployed in the print head.

As an example, consider FIG. 1. There in accordance with one embodiment,a substrate 100 is provided and comprises a heater resistor array 102that includes the heater resistors that are employed to eject ink in theprinthead. Additionally, storage structures 104 are provided on thesubstrate and are formed using the same techniques that are utilized toform the heater resistor array. In the illustrated example, both theheater resistor array and the storage structures are formed such thatthey are electrically addressable. The techniques that can be utilizedto form the heater resistor array and storage structure can comprise anysuitable techniques. For examples of ink jet printing systems thatinclude addressable heater resistor arrays and formation techniques, thereader is referred to the following U.S. Pat. Nos. 6,305,774; 6,412,917;6,318,828; and 5,677,577, all of which are assigned to the assignee ofthis document.

As but one process flow that can be utilized to form resistor arrays andstorage structures, consider the following. The resistor material canfirst be deposited and a metal such as aluminum can be deposited on topof the resistor material. The metal is then patterned into traces and aphoto mask is applied and used to selectively remove aluminum off of thetop of resistor material to form high resistance heater resistors. Anitride/carbide passivation layer is formed over the metal and vias arepatterned and etched therein. Tantalum and gold can then be deposited.Subsequently the gold and the tantalum are patterned and etched toprovide a resultant resistor array and associated storage structures.

As noted above, any suitable material having the characteristic thatannealing changes its resistance value can be used. One exemplarymaterial comprises WSiN. Various WSiN alloys, stoichiometries andprocessing techniques that can be utilized to form ink jet heaterresistors are described in U.S. Pat. No. 6,336,713, assigned to theassignee of this document. Accordingly, for the sake of brevity, suchtechniques will be known by those of skill in the art and are notdescribed here in additional detail.

Other materials can include the general class of Cermet resistormaterials examples of which are metal-silicon oxides (Cr—SiO, W—SiO,Ta—SiO), and metal-silicon nitrides such as WSiN, TaSiN, and the like.

WSiN has been found to have a change in resistance when it is heated orannealed at a high temperature. Experiments with this material haveshown that a resistance decrease from between about 7%-12% occurs whenthe resistors are first heated or annealed. This shift occurs fairlyrapidly and stabilizes at the lower resistance value, where it remainsfor the remainder of the resistor's life. The rapidity with which thisresistance change occurs and the amount of change can be varied bychanging the input voltage across the resistor, and thereby thetemperature. The method by which the resistors are annealed and theoverall degree to which they are annealed is determined by properselection of the pulse width, energy or maximum power per pulse,frequency of the pulses, and total number of pulses applied to theresistor during the annealing process. In one example, a string of 20002.5 micro-sec wide pulses was applied at 20 kHz, with a power betweenabout 0.0015-0.002 Watts per square micron of resistor area for amaterial that is 60:40 mol percent W:Si₃N₄.

As an example, consider FIG. 2 which is a graph that shows the behaviorof a 30×30micron WSiN resistor in which a decrease of resistance occursas a function of use at various voltages. Here, bursts of 100 2.0micro-sec wide pulses at 20 kHz were applied between each measurement.The test was run until an 11% decrease in resistance was observed or2200 pulses had been applied. The data demonstrates that a significantdecrease in resistance can be obtained with the proper selection of athermal cycle. The data also shows that sufficiently low energies do notresult in this change, indicating that unannealed and annealed resistorscan be easily measured without altering their resistance.

Accordingly, in this example, the resistors can be programmed orannealed by applying a short burst of pulses at a properly designedenergy (e.g. 1000 pulses at around 31 volts, 2 micro sec pulse widths at20 kHz). Programming the resistors accordingly can thus result inprogrammed resistors having approximately 7-12% lower resistance valuesthan resistors that were not programmed. Detection of the programmedstate can be accomplished using a comparator to compare programmedresistors to a resistor that has not been programmed. Assuming that theread currents and voltages are substantially lower than the programmingcurrents and voltages, no resistance change will occur in the resistorsduring read cycles. Additionally, since the resistance change observedin WSiN is permanent and does not substantially disrupt or distort thethin film stack used in the inkjet printhead, this method can provide avaluable way to create a small number of identification bits on theprinthead that would not cause disruptions or ruptures in the thin filmlayers upon programming.

FIG. 3 is a flow diagram that describes steps in a method in accordancewith one embodiment. Step 300 forms a heater resistor array over asubstrate. The heater resistor array is a resistor array that isintended for use in a printhead of an inkjet printer. Any suitableformation techniques can be utilized, examples of which are described insome of the patents mentioned above. In addition, any suitable materialcan be used to form the resistors of the resistor array. Step 302 formsone or more storage structures over the substrate. Any suitable storagestructures can be formed. In the illustrated and described embodiment,the storage structures are formed using the same material that is usedto form the resistors of the resistor array. Additionally, in theillustrated example, the storage structures are formed contemporaneouslywith and using at least some of the same process flow that is utilizedto form the heater resistors. One example of a suitable process flow isgiven above.

Advantageously, the material that is selected to form the heaterresistors and storage structures has a characteristic that enables it tobe processed, on a resistor-by-resistor basis, in a manner that cannon-destructibly and non-fusibly change the resistance value of thematerial. In the illustrated example, this processing comprisesannealing selected resistors comprising the storage structures. Byannealing selected resistors, the resistance values of the annealedresistors can be changed and thus the resistors can be used to programdata onto the substrate as noted above.

Step 304 programs one or more of the storage structures using non-fusingtechniques. As noted above, a suitable non-fusing technique comprisesannealing one or more of the resistors and not annealing others of theresistors. It is possible that the resistors comprising the storagestructures can be programmed in ways other than through the annealingprocess.

Using Heater Resistors as a Non-fusible Storage Structure

In accordance with another embodiment, the heater resistors themselvescan be used as a non-volatile, non-fusible storage structure. In thisexample, the resistor material is selected such that it has thecharacteristics mentioned above. Accordingly, one choice for theresistor material is WSiN. Other suitable materials can, of course, beused.

In this embodiment, the selected resistor material has anothercharacteristic or property that is useful for incorporating it as astorage structure. Specifically, when the material is formed to comprisea heater resistor, adjacent resistors or those resistors in closeproximity with one another tend to have similar resistance values. And,although a wafer or die can have a significant variation in resistorvalues across the wafer or die, those resistors that are adjacent or inclose proximity tend to have similar resistance values. This being thecase, adjacent or proximate resistors can be processed differently afterformation to impart to the resistors characteristics that enable theresistors to collectively encode digital data. Specifically, if oneresistor is not annealed, and an adjacent resistor is annealed, then thedifferential in the resistance values of the individual resistors can beused to encode digital data. Thus, after formation and encoding ofdigital data, the heater resistor array can be scanned to identify whichresistors are not annealed and which resistors are annealed. Thisinformation can then be used to access digital data that is encoded onthe die or wafer.

Before describing this embodiment in more detail, consider the followingon the structure and layout of heater resistors. In this embodiment,heater resistors are incorporated into a “pen” which forms part of theinkjet printer's print cartridge. The pen is electrically constructed ofa series of address inputs that drive FETs in rows of a matrix, andprimitive inputs that drive firing resistors in the columns of thematrix. As an example, consider FIG. 4 which shows an exemplary matrixthat comprises firing or heater resistors 400. The heater resistors areorganized into primitive groups—designated P1-P6. Each primitive groupmakes up a column of the matrix. Address inputs Al-A6 are connected tothe drive transistors of, and connect heater resistors in differentprimitive groups. As an example, address input Al is connected to thegates of the drive transistors for the top most heater resistors ofprimitive groups P1 -P6. Ground lines GI-G6 are also depicted.

Individual primitive inputs (PS1-PS6) are commonly connected to theheater resistors of individual respective primitives. As an example,primitive input PSI is connected with all of the individual heaterresistors that make up primitive group P1. Firing a particular heaterresistor is performed by applying an address select signal to an addressinput, and providing an energizing power pulse at its primitive input.So, for example, to fire the top most heater resistor in primitive groupP1, address input A1 is selected and a pulse is applied to primitiveinput PS1. None of the other heater resistors within primitive group P1are fired as their corresponding address inputs have not been selectedat this time. Typically then, the resistors are fired by successivelyand individually driving the individual address inputs and selectivelypulsing the primitive inputs of the heater resistors that are desired tobe fired.

Thus, each and every heater resistor is fabricated to be separately andindividually addressable. In order to function as heater resistors, theresistors are annealed during the fabrication process at the wafer levelbefore die singulation. By choosing not to anneal selected heaterresistors, data can be encoded by virtue of the resistor valuedifferences that are observed between annealed and unannealed resistors.

Typically, heater resistors are annealed at the wafer level through theuse of probes that engage wafer pads, address the heater resistors, andthen apply appropriate annealing pulses to affect the annealing process.Once annealed, the heater resistors can serve as heater resistors. Toselectively encode data at the wafer level, the software code thatdrives the annealing process can be modified such that individualresistors that are desired to be left in the unannealed state can beskipped during the annealing process.

In but one example, each individual die on a wafer is processed tocomprise 2112 heater resistors. These individual die are then singulatedand incorporated into individual pen cartridges. By virtue of the factthat there are 2112 heater resistors, in one embodiment, each die hasthe potential to provide 2112 bits of memory. In other embodiments, alesser number of bits of memory can be provided. This constitutesgreater data storage capacities compared with previously-used on-diefusible links.

The types of information that can be stored on the die can comprise anysuitable type of information that is desirable to associate with aparticular die. Examples of such information include, withoutlimitation, wafer lot, wafer number, wafer row and column number, Dtsr0(ambient reading of an on-die digital temperature sense), electricallockout (to prevent the use of the die in the wrong product),color/black flag (to detect an incorrectly built print cartridge in thefactory), resistor anneal flag (so that the resistor is not annealedtwice), and the like.

It should be noted that the encoding of the data on the die through thenon-fusing techniques can be temporary or permanent. In the event thatthe data is to be temporarily encoded, the resistor or resistors thatare utilized to encode the data can be annealed at some time after theywere skipped in the annealing process. Annealing the heater resistors atsome later time simply involves suitably addressing the resistor(s) tobe annealed and then applying the appropriate energy pulse. Alternately,data can be permanently embodied on the die and hence the printcartridge by simply not annealing the resistors. The implication of thisdecision, however, is that the resistor will not typically be suitablefor use as a heater resistor. If the number of resistors that are usedto encode data is relatively small, then the performance impact on thecompleted pen should be de minimus.

In accordance with this embodiment, the resistors that are selected forencoding data are selected such that they are physically adjacent orproximate one another. In the FIG. 4 example, resistors that are thephysically closest are the resistors that form a common primitive group.As an example, consider FIG. 5 which shows a portion of one primitivegroup of a heater resistor array. In this example, assume that resistorsR1, R3, R4, R5, and R6 have been annealed as usual (as indicated by theboldface representation). Assume also that resistor R2 was skippedduring the annealing process (as indicated by the unboldedrepresentation). By way of example, resistors R1 and R2 can comprise amemory cell that is utilized to encode data. Specifically, when theresistor array is scanned, a determination can be made that theresistance values as between resistors R1 and R2 vary in a manner thatindicates data has been encoded. In this example and by virtue of thefact that resistor R2 is the only unannealed resistor in the primitivegroup, a digital value of 101111 might be encoded where each ofresistors R1 and R3-R6 correspond to a digital value of 1, and resistorR2 corresponds to a digital value of 0. This can be ascertained byvirtue of the following characteristics that annealed versus unannealedresistors share:

-   -   Adjacent unannealed resistors on a die have very similar        resistance values, even though there can be a significant        variation across the entire die;    -   Adjacent annealed resistors on a die have very similar        resistance values; and    -   Adjacent unannealed-annealed resistors have very dissimilar        resistance values.

Thus, for example, when the die is scanned, a determination can be madethat the resistance values of R1 and R2 are sufficiently different as toindicate data has been encoded. Further, the resistance values ofresistor pairs R3/R4, R4/R5, and R5/R6 are sufficiently similar as toindicate that each resistor of the resistor pair has been annealed.Accordingly, since only one of the resistors has not been annealed, thedigital value 101111 has been encoded. Of course, this represents butone encoding scheme only. It is to be appreciated that a wide variety ofencoding schemes can be utilized.

For example, an encoding scheme that encodes one bit per print head canbe utilized. This would constitute a very easy implementation, althoughit represents the least efficient use of the heater resistors. Anexample of the information that might be encoded using this scheme isthe wafer row/column number. Alternately, multiple bits can be encodedper printhead. This approach improves resistor utilization and providesthe basis for a wide variety of encoding approaches. For example, whenencoding multiple bits per printhead, various combinations of resistorscan be utilized such as resistor strings (i.e. resistors that areserially disposed) and the like.

As an example, consider the following in connection with FIG. 6. There,a look up table 600 is provided and is used to map encoded resistors toan encoded value that is associated with the information that is encodedon the die. Table 600 has a first column 602 that is associated with theresistors that have been used to encode the data and a second column 604that is mapped to the combination of resistors that have been encoded.The second column can be used to contain any data that might bedesirable to associate with the die. For example, if resistors R1, R20,R98, R500, and R704 are unannealed, such unannealed resistors might mapto a particular wafer lot number.

It is to be appreciated and understood that a wide variety of mappingsand mapping heuristics might be employed to digitally encode data on thedie using the heater resistors, other than the mechanism(s) described.One embodiment describes a mechanism by which data can be easily andnon-destructively encoded on a print head die using heater resistorsthat are configured to be used as an ink ejecting mechanism.

FIG. 7 is a flow diagram that describes steps in a method in accordancewith one embodiment. Step 700 forms a heater resistor array over asubstrate. This step can be accomplished using any suitable techniqueand using any suitable material. Examples of techniques that can beutilized to form suitable resistor arrays are described in some of thepatents referenced above. An exemplary material that can be used isdescribed above and comprises WSiN. It is to be appreciated that othermaterials can be employed. Characteristics of suitable materials thatcan be employed are described above. After the resistors of the heaterarray have been formed, step 702 anneals multiple resistors of theresistor array. Step 704 encodes data on the substrate by leaving atleast one resistor of the resistor array unannealed. Steps 702, 704 canbe accomplished contemporaneously during the annealing process. Thoseresistors of the resistor array that are desired to be left unannealedcan simply be skipped during the annealing process. This can beaccomplished via a programmatic change that is made to the annealingtool that accomplishes the annealing.

Once the data is encoded, the die or wafer can later be scanned toreveal the encoded data. The encoded data (i.e. the resistors that havenot been annealed) can be used, in some embodiments, as an index into atable that associates useful information with the resistors that areencoded. But one example of how this can be done is given above.

Thus, in this example, selected ink jet heater resistors can bemultifunctional. A first function of the resistor can be to encode dataas described. A second function of the same resistor can be to functionas a heater resistor to eject ink onto a print medium. To impart heaterresistor functionality to a resistor that was previously employed as adata storage structure, the resistor should be suitably annealed. Asnoted above, this can be done at the pen level if so desired.Accordingly, the heater resistor array is configurable in a manner thatimparts to it PROM-like functionality.

In this embodiment PROM-like memory can be provided on the ink jet diewithout any meaningful cost. The heater resistors are already present onthe die; some of them are simply being used as storage structures.Additionally, information can be retained on the die without powerapplied to the die to, for example, refresh the memory. Thus, the memoryis non-volatile. Further, a relatively large number of bits can beprovided on the die, depending on the particular implementation. In oneimplementation, more than 1000 bits can be supplied per die. In anotherembodiment, there is no fusing-induced, thin film damage to thesubstrate which reduces the likelihood of an ink-induced failure.

Conclusion

Various embodiments provide methods and resultant structures that employon-die, non-volatile, non-fusable storage structures on ink jetprinthead die. The embodiments can utilize heater resistor material forthe storage structures to provide PROM-like storage capabilities.Because the resistor material is used to store data in a manner whichdoes not require it to be subjected to fuse-blowing processes, manyissues associated with the fusing-blowing processes are mitigated.

Although the disclosure has been described in language specific tostructural features and/or methodological steps, it is to be understoodthat the appended claims are not limited to the specific features orsteps described. Rather, the specific features and steps are exemplaryforms of implementing this disclosure.

1-8. (canceled)
 9. A method comprising: forming multiple heaterresistors over a substrate, the heater resistors being configured forejecting fluid onto a medium; and forming one or more non-volatile,non-fusable storage structures over the substrate for storing data. 10.The method of claim 9, wherein the acts of forming the heater resistorsand storage structures comprise forming the heater resistors and thestorage structures from the same material.
 11. The method of claim 9,wherein the acts of forming the heater resistors and storage structurescomprise forming the heater resistors and the storage structures from aCermet resistor material.
 12. The method of claim 9, wherein the acts offorming the heater resistors and storage structures comprise forming theheater resistors and the storage structures from the same material, saidmaterial comprising a metal silicon nitride material.
 13. The method ofclaim 9, wherein the acts of forming the heater resistors and storagestructures comprise forming the heater resistors and the storagestructures from the same material, said material comprising WSiN. 14.The method of claim 9, wherein the acts of forming the heater resistorsand storage structures comprise contemporaneously forming material ofsaid resistors and storage structures over the substrate. 15-24.(canceled)
 25. A method comprising: forming, from at least one material,multiple heater resistors over a substrate, the heater resistors beingconfigured for ejecting fluid onto a medium; forming, from said at leastone material, one or more storage structures over the substrate andconfigured to store data; and annealing at least some of the one or morestorage structures sufficient to encode data on the substrate. 26 Themethod of claim 25, wherein the acts of forming comprise forming saidheater resistors and storage structures from a material comprising ametal silicon nitride material.
 27. The method of claim 25, wherein theacts of forming comprise forming said heater resistors and storagestructures from a Cermet resistor material.
 28. The method of claim 25,wherein the acts of forming comprise forming said heater resistors andstorage structures from a material comprising WSiN.
 29. The method ofclaim 25, wherein the acts of forming comprise forming said heaterresistors and storage structures from a material comprising one whoseresistance is a function of whether or not the material has beenannealed.
 30. The method of claim 25, wherein the act of forming saidone or more storage structures comprises forming said storage structuresto comprise part of a heater resistor array comprising the heaterresistors.
 31. The method of claim 25, wherein the act of forming saidone or more storage structures comprises forming said storage structuresto not comprise part of a heater resistor array comprising the heaterresistors. 32-39. (canceled)
 40. A method comprising: forming a fluidejection head substrate to comprise heater resistors and storagestructures; and programming at least some of the storage structureswithout utilizing fusing techniques.
 41. The method of claim 40, whereinthe act of forming comprises forming the heater resistors and thestorage structure from the same material.
 42. The method of claim 40,wherein the act of forming comprises forming the heater resistors andthe storage structure from a Cermet resistor material.
 43. The method ofclaim 40, wherein the act of forming comprises forming the heaterresistors and the storage structure from WSiN.
 44. The method of claim40, wherein the act of programming comprises annealing at least some ofthe storage structures and not annealing others of the storagestructures.
 45. The method of claim 40, wherein the act of forming theheater resistors and the storage structures comprises forming thestorage structures to comprise part of a heater resistor array thatcomprises the heater resistors. 46-52. (canceled)
 53. A methodcomprising: forming, over a fluid ejection device substrate, storagestructures comprising a material; forming, over the fluid ejectiondevice, heater resistors comprising said material; said material havinga first resistance value before annealing and a second differentresistance value after annealing; and wherein encoded data can beascertained by observing differences in resistance values betweenannealed and unannealed material.
 54. A method comprising: forming, overa fluid ejection device substrate, storage structures supported by thesubstrate; and forming heater resistors that can be utilized to ejectfluid, said forming heater resistors being performed contemporaneouslywith said forming storage structures and using at least some of the sameprocess flow that is utilized to form said storage structures.
 55. Amethod comprising: forming a fluid ejection head substrate to compriseheater resistors and storage structures; and programming at least someof the storage structures without utilizing fusing techniques, saidprogramming being performed by applying at least one burst of pulses atan energy sufficient to impart to programmed storage structuresresistance values having between about 7-12% lower values than heaterresistors or storage structures that were not programmed.
 56. A methodcomprising: forming a fluid ejection head substrate to comprise heaterresistors configured to eject fluid; and annealing selected heaterresistors, resistance values of said selected heater resistors beingmodified by said annealing sufficient to program data onto the fluideject head substrate.
 57. A method comprising: forming a fluid ejectionhead substrate to comprise heater resistors configured to eject fluid;and annealing at least one heater resistor sufficient to modify itsresistance value; and not annealing a heater resistor adjacent said atleast one heater resistor, said heater resistors having differentresistance values sufficient to enable data to be encoded on thesubstrate.
 58. A method comprising: forming a fluid ejection headsubstrate to comprise heater resistors configured to eject fluid; andencoding data on the substrate by leaving at least one heater resistorunannealed.
 59. A method comprising: forming a fluid ejection headsubstrate to comprise a plurality of heater resistors, at least oneheater resistor being formed to have at least two different functions; afirst function comprising a function that can encode data on thesubstrate; and a second function comprising a function that can ejectfluid.
 60. A method comprising: configuring a fluid ejection headsubstrate to comprise a plurality of heater resistors; and retaining,with at least some of the heater resistors, information on the substratewithout power being applied to the substrate. 61-63. (canceled)